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Micrometer-sized domains

It is a routine SFM experiment to investigate the heterogeneous structure of polymer blends and composites containing micrometer sized domains [69]. A less trivial problem is to resolve and characterise the features on the nanometer scale (around 10 nm), which are comparable to the tip size and the contact area. Typical systems, which demonstrate microheterogeneous structures, are block copolymers consisting of chemically different and physically incompatible blocks, e.g. A and B. As a result of the interconnectivity of the blocks, block copolymers undergo microphase separation, where the size of the microdomains is restricted to the molecular dimensions. One can distinguish between AB diblock copolymers and triblock copolymers (ABA and ABC). [Pg.105]

The length parameters ro and Ro manifest a common scaling factor of 10 between the (" He) cluster and the atomic condensate. These length scales move from the nanometer size domain for (" He) clusters to the micrometer size domain for the condensate. [Pg.253]

Multiscale surface structures have been directly obtained by simple spin-coating from diblock copolymer/homopolymer blends. For instance. Park et al. [89] prepared films from PS-b-P2VP/PMMA blends. These films were prepared from a selective solvent either for PS or PMMA. The pure block copolymers (BCP) form nanometer-sized micelles as a consequence of the microphase separation due to the incompatibility between the constituent blocks (Fig. 6.13(a)). However, blending the BCP with a homopolymer induces macrophase separation between the BCP micelles and the PMMA and the formation of isolated PMMA micrometer-size domains (Fig. 6.13(b)-(e)). Other groups including Jeong et al. [50] or Ibarboure et al. [42] also used homopolymer/BCP blends to fabricate multiscale ordered surfaces. Jeong and coworkers used P(S-b-MMA)/PMMA blends with variable composition. [Pg.148]

Polarized light microscopy has shown micrometer-sized domains in the thermotropic LCPs aligned along the fiber axis. The meander of the domains is consistent with their polarization colors (Fig. 5.87, color section). The domains... [Pg.299]

Two different kinds of micrometer-sized domains were observed in monolayers of PS with 10 methylene groups when the aqueous phase contained 20 pM Ca " prior to the film formation [32]. One type of domains produced lower feedback current compared to the feedback in the absence of Ca +. The stronger blocking effect was attributed to solidification of the lipid film in the presence of Ca + ions. Another type of domains exhibited lower blocking effect as compared to Ca +-free lipid films, which was explained by clustering of pinhole defects. Stable SECM images of two types... [Pg.210]

Macro domains of micrometer size have been reported when using an ordinary microscope. The typical procedure is to use 2% of a fluorescent lipid analog, which renders visible a domain pattern. This, of course, assumes that the fluorescence moiety has no effect on the assembly structure. There is (generally) no information about the thickness of the domains. The shapes of domains are varied, and very complex (circular or near-circular domains, parallel stripes, or more irregular, wormlike, or similar kinds of structures). [Pg.217]

Thus two different eb methods may be considered. The first method is direct eb domain writing when uncoated fe crystal is directly subjected to the electron beam [45-48]. The previously published data and our results on direct eb domain tailoring showed that inversed domains in LiNbC>3 crystals occupy micrometer-size homogeneously polarized areas. [Pg.201]

As distinct from uncharged droplets, flocculation in the range of micrometer-sized droplets is possible. As seen in Fig. 9, even rather large droplets (4 pm) aggregate reversibly if file electrolyte concentration is lower than (1-5) X10 M and the Stem potential is higher than 25 mV. For smaller droplets the domain of flocculation will extend while the domain of coagulation will shrink. For submicrometer droplets, flocculation takes place even at high electrolyte concentrations (0.1 M). [Pg.86]

Nevertheless, it is important to point that, though the use of a compatibilizer (e.g., DBCs acting as a macromolecular surfactant and form a layer at the interface between the two homopolymers, thereby reducing the interfacial tension between the two domains and stabilizing the microscopic morphologies) can improve the phase stability, but it often result in micrometer to sub-micrometer size discontinuous (islands of minor phase in pool of major phase) dispersion of phases (as shown schematically in... [Pg.35]

SECM microfabrication is based on the use of the tip to alter local chemical properties in small (micrometer or submicrometer-sized) domains. Several approaches to surface modification by SECM are outlined in this section. These may be divided roughly into methods in which the tip and substrate are the working electrode and auxiliary electrodes of a cell and methods in which the chemistry of the system is chosen so that the SECM feedback process leads to deposition or... [Pg.477]

The Ostwald ripening process had been previously investigated in monolayers of tetradodecyloctathio-phene (6) deposited from a 1,2,4-thrichlorobenzene solution [38]. The process was followed by STM in real time, on the molecular length scale. On a time scale of seconds, the size decrease of small domains up to their disappearance was paralleled by the increase in size of larger domains. Over a period of several minutes to a few hours, single crystals of micrometer size developed from 2D polycrystals. The rate of the Ostwald ripening process was controlled by the reorientation of the domain boundaries of the 2D polycrystais. [Pg.521]

The diversified porous patterns of diatomaceous silicas are on the nano- to submicrometer scale (< 10-300 nm) and these meso- and macropores cannot be mediated by single macromolecules, not even proteins. To mimic these meso- and macroporous structures, a different approach can be applied based on a phase separation process as in the vesicle-mediated macromorphogenesis processes extensivily reviewed in Pickett-Heaps et al.I 1 In this case oil-in-water (0/W) emulsions are applied as a model system. 0/W emulsions are isotropic and thermodynamically stable liquid media with a continuous water domain and an oil domain, which are thermodynamically stabilized by a surfactant as micrometer-sized liquid entities. [Pg.390]

We will discuss several strategies to tether the properties of LCE actuators to certain specifications, and then present examples of actuator systems of different shapes and different domain sizes. We shall differentiate between macroscopic and microscopic LCE actuators. Films (Sect. 2.2.1) and fibers (Sect. 2.2.2) typically have at least one macroscopic dimension. Microscopic actuation systems from LCEs have received much interest lately and have recently been the subject of a specialized review [88]. In Sect. 2.2.3, we will discuss micrometer-sized actuators that are fixed on a solid substrate to yield stunuU-responsive surfaces. In Sect. 2.2.4, we will review several methods for preparation of coUoid-like actuators that are freely suspended in air or in a surrounding Uquid. [Pg.62]


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See also in sourсe #XX -- [ Pg.147 ]




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Domain size

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